Dear Mariko, 

It is great that you are looking into this ahead of time and making a plan!  

Job-based insurance allows you to delay Medicare enrollment in many cases. There are two questions to consider:  

• Will I have an opportunity to enroll in Medicare Part B later without a penalty and without waiting for a specific time of year? 
• Will my job-based insurance pay primary on my health care claims? 

In other words, before you delay enrollment, you should determine whether you will have a Part B Special Enrollment Period (SEP) and whether your job-based insurance pays primary or secondary. 

In most cases, you should only delay Part B if you will have an SEP and your job-based insurance is the primary payer (meaning it pays first for your medical bills) and Medicare is secondary. 

Part B Special Enrollment Period 

Because you will be eligible for Medicare due to age (meaning you will be 65+) and are covered by your spouse’s job-based insurance, you will have a Special Enrollment Period (SEP) to enroll in Part B while you have that coverage from current work up to eight months after the coverage or the work ends (whichever is first). This means that you can enroll in Part B after your Initial Enrollment Period (IEP) ends without facing a penalty and without having to wait for the General Enrollment Period (GEP).  

Primary or secondary job-based insurance 

Next, consider whether your job-based insurance will be the primary payer. 

• Job-based insurance is primary if it is from an employer with 20+ employees. Medicare is secondary in this case, and some people choose not to enroll in Part B because of the additional monthly premium. 
• Job-based insurance is secondary if it is from an employer with fewer than 20 employees. Medicare is primary in this case, and if you delay Medicare enrollment, your job-based insurance may provide little or no payment. You should enroll in Part B for coverage when you are first eligible. 

Note: There are different rules about the SEP and which insurance is primary if you are Medicare-eligible due to disability or because you have ESRD. 

To find out if your job-based insurance is primary or secondary, contact your or your spouse’s human resources department for information about your employer’s size. If you plan to delay enrollment into Part B and use the SEP later, keep records of your health insurance coverage. You will be required to submit proof of your enrollment in job-based insurance when using the SEP to enroll in Part B later. Proof of enrollment in job-based insurance includes: 

• Written notice from your employer or plan 
• Documents that show health insurance premiums paid, including W-2s, pay stubs, tax returns, and/or receipts 
• Health insurance cards with the appropriate effective date 

Note: If you have insurance from an employer that is not because of current work, like COBRA or retiree insurance, there are different rules for the SEP and which insurance is primary. 

In summary, you should find out if your husband’s insurance will be primary to Medicare. If it is primary, then you can delay Medicare enrollment if you’d like, since you would already have primary insurance from your husband’s current work.  

I hope this helps you decide whether or not to enroll in Medicare during your Initial Enrollment Period! 

-Marci